As disclosed in JP-A-2010-151808 (corresponding to US 2010/0126269), an integrated microelectronicmechanical structure is well known. In this structure, a driving mass is fixed to a substrate via an elastic anchor. The driving mass is actuated by a driving movement around a vertical axis, thereby performing a rotary movement on a plane perpendicular to the vertical axis. When an angular velocity is applied to the moving driving mass, the angular velocity generates a Coriolis force on the driving mass. In the microelectronicmechanical structure disclosed in JP-A-2010-151808, the angular velocity is detected by detecting a displacement of the driving mass caused by the Coriolis force.
As shown in FIG. 4 of JP-A-2010-151808, the driving mass has an annular shape. In the microelectronicmechanical structure, a first anchor is arranged in a first region, which is surrounded by an inner surface of the annular driving mass. Further, four second anchors are arranged in a second region, which is defined as an outside region of an outer surface of the annular driving mass. Further four first elastic anchors are arranged in such a manner that the first anchor is coupled to one end of each first elastic anchor and the other end of each first elastic anchor is coupled to the inner surface of the annular driving mass. Further, four second elastic anchors are arranged in such a manner that one end of each second elastic anchor is coupled to the outer surface of the annular driving mass and the other end of each second elastic anchor is coupled to a corresponding second anchor. With this arrangement, the driving mass is supported by the anchors via eight elastic anchors.
As described above, in the microelectronicmechanical structure disclosed in JP-A-2010-151808, one end of each elastic anchor is coupled to the driving mass and the other end of each elastic anchor is coupled to a corresponding anchor that is fixed to the substrate. In this structure, the vibration generated by the driving mass is transmitted to the anchors via the elastic anchors. Then, the vibration transmitted to the anchors reflects on the substrate and the reflected vibration is transmitted back to the driving mass via the elastic anchors. Thus, a movement state of the driving mass becomes unstable, thereby decreasing a sensitivity of angular velocity detection.